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The maximum and minimum values of -4l...

The maximum and minimum values of
`-4le5cos theta+3cos(theta+(pi)/(3))+3le10` are respectively

A

`4 and -4`

B

`10 and -4`

C

`10 and -10`

D

`6and -4`

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The correct Answer is:
To find the maximum and minimum values of the expression \(-4 \leq 5\cos(\theta) + 3\cos\left(\theta + \frac{\pi}{3}\right) + 3 \leq 10\), we will follow these steps: ### Step 1: Rewrite the Expression We start with the expression: \[ 5\cos(\theta) + 3\cos\left(\theta + \frac{\pi}{3}\right) + 3 \] Using the cosine addition formula, we can rewrite \(\cos\left(\theta + \frac{\pi}{3}\right)\): \[ \cos\left(\theta + \frac{\pi}{3}\right) = \cos(\theta)\cos\left(\frac{\pi}{3}\right) - \sin(\theta)\sin\left(\frac{\pi}{3}\right) \] Since \(\cos\left(\frac{\pi}{3}\right) = \frac{1}{2}\) and \(\sin\left(\frac{\pi}{3}\right) = \frac{\sqrt{3}}{2}\), we have: \[ \cos\left(\theta + \frac{\pi}{3}\right) = \frac{1}{2}\cos(\theta) - \frac{\sqrt{3}}{2}\sin(\theta) \] ### Step 2: Substitute Back into the Expression Substituting this back into the expression gives: \[ 5\cos(\theta) + 3\left(\frac{1}{2}\cos(\theta) - \frac{\sqrt{3}}{2}\sin(\theta)\right) + 3 \] This simplifies to: \[ 5\cos(\theta) + \frac{3}{2}\cos(\theta) - \frac{3\sqrt{3}}{2}\sin(\theta) + 3 \] Combining the cosine terms: \[ \left(5 + \frac{3}{2}\right)\cos(\theta) - \frac{3\sqrt{3}}{2}\sin(\theta) + 3 = \frac{13}{2}\cos(\theta) - \frac{3\sqrt{3}}{2}\sin(\theta) + 3 \] ### Step 3: Find the Maximum and Minimum Values Now, we need to find the maximum and minimum values of: \[ \frac{13}{2}\cos(\theta) - \frac{3\sqrt{3}}{2}\sin(\theta) \] This can be expressed in the form \(R\cos(\theta + \phi)\), where: \[ R = \sqrt{\left(\frac{13}{2}\right)^2 + \left(-\frac{3\sqrt{3}}{2}\right)^2} \] Calculating \(R\): \[ R = \sqrt{\frac{169}{4} + \frac{27}{4}} = \sqrt{\frac{196}{4}} = \sqrt{49} = 7 \] Thus, the maximum value of \(\frac{13}{2}\cos(\theta) - \frac{3\sqrt{3}}{2}\sin(\theta)\) is \(7\) and the minimum value is \(-7\). ### Step 4: Adjust for the Constant Now, we need to add \(3\) to both the maximum and minimum values: - Maximum: \(7 + 3 = 10\) - Minimum: \(-7 + 3 = -4\) ### Final Result Thus, the maximum and minimum values of the original expression are: \[ \text{Maximum value} = 10, \quad \text{Minimum value} = -4 \] ### Summary The maximum and minimum values of the expression \(-4 \leq 5\cos(\theta) + 3\cos\left(\theta + \frac{\pi}{3}\right) + 3 \leq 10\) are \(10\) and \(-4\), respectively.

To find the maximum and minimum values of the expression \(-4 \leq 5\cos(\theta) + 3\cos\left(\theta + \frac{\pi}{3}\right) + 3 \leq 10\), we will follow these steps: ### Step 1: Rewrite the Expression We start with the expression: \[ 5\cos(\theta) + 3\cos\left(\theta + \frac{\pi}{3}\right) + 3 \] Using the cosine addition formula, we can rewrite \(\cos\left(\theta + \frac{\pi}{3}\right)\): ...
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OBJECTIVE RD SHARMA ENGLISH-TRIGONOMETRIC RATIOS AND IDENTITIES-Chapter Test
  1. The maximum and minimum values of -4le5cos theta+3cos(theta+(pi)/(3...

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  2. If cosalpha+cosbeta=0=sinalpha+sinbeta, then cos2alpha+cos2beta is equ...

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  3. If sin beta is the GM between sin alpha and cos alpha, then cos 2beta...

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  4. tan^(2pi)/(5)-tan^(pi)/(15)-sqrt(3)tan^(2pi)/(5)tan(pi)/(5) is equal t...

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  5. If sinB=1/5sin(2A+B), then (tan(A+B))/(tanA) is equal to

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  6. (sin7theta+6sin5theta+17sin3theta+12sintheta)/(sin6theta+5sin4theta+12...

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  7. If (cos(theta(1)-theta(2)))/(cos(theta(1)+theta(2)))+(cos(theta(3)+the...

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  8. (1+cos56^(@)+cos58^(@) -cos66^(@))/(cos28^(@)cos29^@sin33^(@)) =

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  9. alpha and beta are acute angles and cos2alpha = (3cos2beta-1)/(3-cos2b...

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  10. If cosectheta=(p+q)/(p-q), then cot(pi/4+theta/2)=

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  11. If sinalpha+sinbeta=a ,cosalpha+cosbeta=b=>sin(alpha+beta)=

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  12. If cos(alpha+beta)=(4)/(5) and sin(alpha-beta)=(5)/(13) , where alpha ...

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  13. about to only mathematics

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  14. The value of sum(k=1)^(3) cos^(2)(2k-1)(pi)/(12), is

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  15. If (a^(2)+1)/(2a)=costheta, then (a^(6)+1)/(2a^(3))=

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  16. The greatest integer less than or equal to (1)/(cos 290^(@))+(1)/(sqrt...

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  17. If tan alpha=(1+2^(-x))^(-1), tan beta=(1+2^(x+1))^(-1) then alpha+bet...

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  18. A and B are positive acute angles satisfying the equations 3cos^(2)A...

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  19. If T(n)=cos^(n)theta+sin ^(n)theta, then 2T(6)-3T(4)+1=

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  20. The maximum value of 1+8sin^(2)x^(2)cos^(2)x^(2) is

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  21. about to only mathematics

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